This invention relates to a reflecting mirror-equipped GPS (Global Positioning System) receiving antenna apparatus, i.e., an antenna apparatus which receives radio waves transmitted from GPS satellites and which is equipped with a reflecting mirror for use in a conventional electronic distance meter (EDM) (tachymeter) or a total station.
Conventionally there is known a GPS interferometer measuring method in which the radio waves transmitted from GPS satellites are received by microstrip type of antennas disposed at two distant points, coordinate values at these two points (i.e., coordinate values with the earth's center as an origin) are obtained, and the distance between the two points is calculated from these values. An antenna apparatus to be used in this measurement comprises an antenna mounted on a tripod and a receiver connected to the antenna. The signals received by the antenna are calculated by the receiver, thereby indicating the coordinate values of the point.
The above-described antenna apparatus is equipped only with a function of receiving the radio waves from the GPS satellites. When the radio waves are prevented by a building or the like from reaching the antenna, they cannot be received by the antenna. Then, in case the measurement is carried out by an electronic distance meter or a total station by making the position at which the antenna is set as a survey point, the antenna apparatus must be removed to place therein a reflecting mirror apparatus instead. Consequently, the measurement with the conventional antenna apparatus is time-consuming and it cannot be done quickly.